Gyrating programmable scanner

ABSTRACT

A device for providing angular displacement of an axis in a direction selected from the X or Y direction or rotational movement about the Z direction with respect to the axis. The device comprises a magnetic core element which produces a magnetic field and defines a Z axis. The core element is capable of displacement in the X and Y directions respectively, and also rotational movement about the Z axis. A coil device proximate the core element introduces a distortion force in the core element in at least one of the X and Y directions or about the Z axis as desired a mounting device suspends the core element with respect to the coil means to permit relative movement therebetween in response to the distortion force.

This application is a divisional of application Ser. No. 08/273,101filed on Jul. 8, 1994, U.S. Pat. No. 5,596,442, which is a ContinuationIn Part Application of patent application Ser. No. 07/612,983 filed Nov.15, 1990, U.S. Pat. No. 5,187,612.

TECHNICAL FIELD

The present invention relates to a device for providing movement on anaxis in at least one direction selected from the rotational directionand the x or y direction. More particularly, the invention relates to adevice suitable for controlling the movement of a beam of light, such asfrom a laser, to generate two dimensional repeating patterns of light.In one embodiment, the invention is useful as a scanner for moving asmall spot of light across bar codes in order to read them.

BACKGROUND ART

Scanners are devices which are used to control the movement of a beam oflight, such as from a laser. The scanners are employed to aim opticalelements such as mirrors, lenses and the like in order to reflect,collect and focus light. Scanners have found extensive application inthe bar code industry. Bar codes consist of alternating light and darkbars which are used to present price or other information. Oneconventional method for reading them is to scan a focused beam of lightin a line across the entire code. As light is absorbed and scattered bythe bars, the resulting light modulation may be detected by aphotodiode, for example, and processed by an electronic cash register orcomputer terminal.

In hand held bar code reading equipment compactness and simplicity ofthe scan mechanism are essential so the equipment can be portable.Single straight line scans are the simplest to generate and thus areoften used in such equipment.

Orientation of the scanning beam with respect to the bar code isrequired however and this can slow down the reading process in eitherportable or fixed mount scanners. Various systems have therefore beendevised to automatically scan a beam in multiple directions to overcomethe need for tedious orientation.

U.S. Pat. No. 4,387,297 disclosed a portable scanning system in which apair of motors and multiple drives are used to generate anomnidirectional pattern. Refinements of this device have not yetobviated the inherent clumsiness and size of the device due to themultiple drives and other equipment. Another beam scanning type device,shown in U.S. Pat. No. 4,639,070, uses an involved gear system forrotating various elements of the device. It also is quite complicated tomanufacture.

U.S. Pat. No. 4,041,322 describes a device in which there is an angulardisplacement of a mirror in a single plane and at a constant speed.Several mirrors are used to provide the scanning signal at variousangles.

U.S. Pat. No. 4,494,024, describes a spring activated motor, but it is a"one shot" spring driven motor in which heat is used to release torqueby severing a chord. U.S. Pat. No. 3,631,274 describes a power supply inwhich a spring induces a voltage pulse in the coil.

U.S. Pat. No. 4,388,651 describes the faults of the prior art, statingthat it is characterized generally by considerable complexity or bylimited performance. This patent proposes to solve the problem using asingle, small diameter rotating polygon mirror which is described ashaving increased scan efficiency by reflecting a beam from the polygonmirror facets two separate times. Examples of other systems are shown inU.S. Pat. No. 4,794,237, which employs a plurality of mirrors and arotating disc, and in U.S. Pat. No. 4,795,224 which requires severalmotors and a relatively complicated prism ring which refracts light.

None of the prior art has yet been able to generate an appropriateoptical pattern of lines to read bar codes at any orientation. Moreover,no prior art device has been found to produce omnidirectional scanpatterns with a single optical element. Ideally, such a device would besmall and very rapid, and could be held in one hand if constructed as araster or omnidirectional device. It is desirable that the device beprogrammable to present one or more than one pattern of light with thefewest possible parts.

It is an object of this invention to provide a device for providingmovement on an axis, such that a mirror can be attached to that axis, inorder to impart combinations of rotational and x or y movement.Preferably the device imparts both movements, in order to generate a twodimensional scanning pattern produced by light reflected off on themirror.

It is a particular object of the present invention to produce laser scanpatterns which greatly reduce or eliminate the need for specialorientation of either the bar code or the scanner in bar code readingequipment.

Yet another object is to provide a scanner which is programmable and yetwhich is small and compact, and which operates at low power.

In it broadest form, the object of this invention is to provide a meansfor aiming or positioning an optical element in synchronization withelectronic signals, which may be produced by oscillators, computers,music, voice, and the like, for information gathering or demonstrationor entertainment purposes.

Other objects will appear hereinafter.

DISCLOSURE OF INVENTION

It has now been discovered that the above and other objects of thepresent invention have been accomplished in the manner described below.Specifically, the invention relates to a device for providing movementon an axis in at least one direction selected from the x or y directionand the rotational direction, and preferably in several directions,preferably simultaneously.

The device includes a shaft member having an axis defining a rotationaldirection about the axis of the shaft. A magnetic core means is mountedon the shaft and centers the shaft on the axis. The shaft itself mayextend in one or both directions axially or may be the center of thecore. The core generates a magnetic field in a plane which defines x andy coordinates with respect to the axis. Also included is a ferromagneticring surrounding the core and aligned in the plane described above. Thering has a coil means for receiving a varied electric current in thecoil which is wrapped about the ring. The ring is positioned to providea low reluctance path for the magnetic field and the magnetic field isaligned to penetrate only one side of the coil. Finally, means areprovided for suspending the core with respect to the coil to permitrelative movement therebetween in response to the varying frequencycurrents. Movement of the core causes movement on the shaft in at leastthe x-y direction or the rotational direction or combinations thereof.

In a preferred embodiment, the suspending means comprises at least oneflat spring or elastic member which flexibly mounts the core withrespect to the coil. The spring provides a restoring rotational torqueto the core about the axis.

In another embodiment, the device is adapted to receive a firstfrequency that is a resonant frequency of the mounting means in therotational direction. It is further adapted to receive a secondfrequency a resonant frequency of the mounting means in the x-ydirection. It is contemplated that the device would further includefrequency mixer means for supplying various frequencies to the coil, andpreferably at least the two resonant frequencies to the coil.

In yet another embodiment, a second coil is added. This coil isannularly positioned around the magnetic core and is located in theregion of the magnetic field which defines the x and y coordinates.Preferably, the coil is wound around a bobbin device which locates theannular coil between the ring and the magnetic core. Means are providedfor introducing electric current into the annular coil.

It is further contemplated that a mirror will be mounted on the axis,and the entire device can be incorporated into a scanner system asdesired.

It is further contemplated that another kind of optical element such asa small semi conductor laser device may be directly mounted to the axisand mounted into a scanner system.

In one embodiment, the annular ferromagnetic ring includes a gap in itsperiphery at a location radially opposite the coil that is wound on thering. In some instances, the coil may in fact comprise two coils, eachof which is wound at a location spaced approximately 90° radially fromsaid gap. In that embodiment, the magnetic core element may be sized tohave a length facing the gap and also facing that portion of the ringperiphery which is 180° radially from the gap. The core element width isshorter than the length because the two coils extend into the annularspace. This generally rectangular shape increase the efficiency of thedevice.

Finally, in another embodiment, the ring may include a radially inwardlyfacing ferromagnetic screw which functions as a magnetic damper means.The screw is threaded in the ring to adjustably vary the distancebetween the radially inwardly facing end of the screw and the coreelement.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the present invention and the variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawings, where:

FIG. 1 is a perspective view of one embodiment, shown in combinationwith a laser source and a mirror, and also shows an output pattern.

FIG. 2 is an exploded view of a device similar to the device shown inFIG. 1.

FIG. 3 is a schematic view of a preferred driving mechanism showingmagnetic field lines of force for a ring and magnetic core of the deviceshown in FIG. 1.

FIG. 4 is a section view taken along line 4--4 of FIG. 3, showing thedirection of the current in the coil around the ring.

FIG. 5 is an exploded perspective view of another simpler embodiment ofthe present invention.

FIG. 6 is an exploded view of the preferred embodiment of thisinvention.

FIG. 7 is a cross sectional view of a device of the type shown in FIG.6, in which the assembled device is sectioned.

FIG. 8 is a cross sectional view of an alternative embodiment of thedevice shown in FIGS. 6 and 7.

FIG. 9 is a perspective view showing arrangement of the shaft andsprings under various forces caused by different frequency current inthe coil.

FIG. 10 is an exploded perspective of yet another alternative embodimentof the present invention.

FIG. 11 is a perspective view of another embodiment, shown incombination with a laser source and a mirror, and also shows a twodimensional raster output pattern.

FIG. 12 is an exploded view of a device similar to the device shown inFIG. 11.

FIG. 13 is an exploded perspective view of yet another embodiment of thepresent invention.

FIG. 14 is a schematic view of a preferred driving mechanism showingmagnetic field lines of force for a ring and magnetic core of the deviceshown in FIG. 13.

FIG. 15 is an exploded perspective view of still another embodiment ofthis invention.

FIG. 16 is a schematic view of the device shown in FIG. 15, showingmagnetic field lines of force for that ring and core.

FIG. 17 is an enlarged schematic view of a device similar to that shownin FIG. 13, showing yet another embodiment and the magnetic field linesof force for that device.

FIG. 18 is a cross-sectional view of a device which permits compactmounting and can produce large rasters or other two dimensional scans.

FIG. 19 is a view of a device similar to that of FIG. 18 showing asample scan pattern.

FIG. 20 is a cross-sectional view of the present invention which allowsa beam of light to enter one end of the device and produces a scannedbeam which exits the opposite end of the device.

FIG. 21 is a view of the device of FIG. 20 showing how it may bearranged for a compact in-line scan system.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, a laser beam is generated from a laser source 11 andis reflected by mirror 13 which, as will be described below, is movingin at least one or two dimensions to cause a pattern 15 to be reflectedoff of mirror 13.

While the present invention is admirably suited for use as a scannerwith a laser source and the like, those components are not shown. Theinvention relates to the movement of the axis of a shaft in at least thex-y direction or the rotational direction. Specifically, shaft 17 hasaxis 19 and is caused by the present invention to rotate in therotational direction as shown by arrow 21 and in the x-y plane as shownby arrows 23 and 24.

Shaft 17 causes mirror 13 to move in the rotational direction or the x-yplane by the magnetic rotor and coil arrangement contained in frame 25.The position of the magnet is restored by spring 27 as the magnet movesdue to interaction with current in the coil at various frequencies.Ideally, the frequency of the current in the coil will cause rotation inboth the rotational direction and the x-y directions. In FIG. 1, arotating ellipse pattern is shown, but an almost unlimited number ofpatterns are possible. While spring 27 is preferred in this embodiment,other mounting means for flexibly suspending a core may be used. Ofthese, flat springs, flexible elastic members, and membranes arepreferred.

Turning now to FIG. 2, a device similar to that of FIG. 1 is shown. Thedevice is shown with its major components on an axially exploded view.Mounted on the shaft 17 is a magnet 29, with arrow 30 pointing in thedirection of magnetization.

The lower end 31 of shaft 17 is supported in the base frame 25 such asshown in FIG. 5. Positioned radially from the magnet 29 is a toridalring 35 which includes at least one winding 37, so that the ring 35functions as a coil for cooperative action with magnet 29. Spring 27 ismounted on ring 35 through a pair of posts 32 which fit into holes 34 inthe spring. The interior portion of spring 27 has a shaped slot 36 whichfits over the central cooperative member 38 of magnet 29. Thus movementof magnet 29 with respect to core ring 35 will cause a restoring forcein spring 27, as post 32 and hole 34 restrains movement of the springwhile shaped slot 36 and central core 38 cause the inner portion ofspring 27 to move with magnet 29.

Turning now to FIG. 3, the magnet 29 is shown with a north and southpole, generating a magnetic field of flux 39 so that ferromagnetic ring35 provides a low reluctance path for field 39 from the north pole tothe south pole. Flux lines 39 pass through the gap 41 between the magnetcore 29 and the ferromagnetic ring 35 and also interact with currentconducted by winding 37.

When current is passed through winding 37, the direction of the currenton the portion of the winding 37 around the outside of torrid ring 35will be opposite that of the current direction on the inside wall ofring 35. Note that the field 39 does not pass through the part ofwindings 37 on the outside diameter of ferromagnetic ring 35 makingpossible a torque to be generated between the magnetic core and thewinding. The magnetic field produced by this winding 37 will also becontained and directed by the ferromagnetic material of ring 35. Currentin coil 37 is not allowed to reach a level which would cause core 35 toreach a state of magnetic saturation.

When permanent magnet rotor 29 is introduced into the center of ring 35,its field will pass through the air gap 41 and enter the inside wall ofring 35. The field 39 will then be directed as shown by the arrowsaround the circumference and returned through the air gap near theopposite pole of the magnet, thereby finally completing its path. Thefield of the permanent magnet 29 does not substantially penetrate beyondthe outer wall of the ring 35. If the magnetic field of magnet 29penetrated the outer wall of ring 35, and thus through the outside coilwindings 37, deflection forces would cancel and the rotor 29 wouldexperience no torque. However, since the magnetic material or lowreluctance path of ring 35 directs and contains the magnetic field 39 ofmagnet 29, and shields coil windings 37 passing up the outside wall ofthe ring 35, from the field of magnet 29, the magnetic field of magnet29 passes only through one side of the winding. When a current carryingconductor is placed in a magnetic field which is perpendicular to thedirection of the current, a force between the current and the field isproduced which is mutually perpendicular to both the direction of thecurrent and the magnetic field. Thus, as shown in FIG. 3, a force willbe produced between a field 39 and the current in coil 37. As a result,magnet 29 will experience a torque which causes it to rotate. Thistorque is proportional to the number of turns of wire, the currentcarried by the coil, and the magnitude of the magnetic flux from themagnet penetrating the inside portion of the winding. Introduction of analternating current in coil 37 will cause magnet 29 to oscillate.

Turning back to FIG. 2, it is noted that the magnet 29 is fitted throughthe central portion 38 of magnet 29 to the shaped slot 36 on spring 27,thus, as magnet 29 moves or vibrates about axis 19 of shaft 17, spring27 opposes that motion. When an alternating current is introduced incoil 37, at a resonant frequency, in the rotation direction for spring27, movement of the mirror 13 is caused to occur in the rotationaldirection. Similarly, when the current in coil 37 is at a frequency ator near the resonant frequency for movement of spring 27 in the x-yplane, movement in that direction is also achieved. Notice that mirror13 is shown with its mounting hole for shaft 17 off center therebycreating a slightly unbalanced load for shaft 17. Said unbalanced loadacts to aid the initiation of and to sustain oscillating motion in thex-y dimensions when appropriate resonance frequencies are introducedinto coil 37 for those modes of oscillation.

In another preferred embodiment, shown in FIG. 2, a second spring 49 isalso mounted with post 51 through holes 53 in the same manner as spring27 is supported by holes 34 on posts 32. Thus, excitation of the magnet29 by current in coil 37, as previously described will be resisted byboth spring 27 and spring 49 to provide the restoring forces necessaryfor oscillation. Selection of suitable frequencies of the current to beresonant with springs 27 and 49 will allow even greater variety in theultimate movement of the mirror 13 in both the rotational direction andthe x-y plane.

FIG. 6 shows the preferred embodiment of this invention, in which thefirst coil 37 and ring 35 is augmented with a second coil. An annularcoil 45 is wound around bobbin 47, so as to present an annular windingin the plane of the magnetic field of magnetic core 29. Bobbin 47 issized to fit in space 41 shown empty in FIG. 3 and filled with bobbin 47in FIG. 7.

The second coil, annular coil 45, is also connected to an electriccurrent source, not shown, so that a varied current can be introducedinto coil 45. Again, various frequencies and wave forms will causerelative movement between magnetic core 29 and bobbin 47, primarily butnot exclusively in the x and y plane.

When both the first coil 37 and annular coil 45 are energized withcurrent at various independent frequencies the magnetic core 29 may bemade to move in combinations of rotational and x-y directions which arenot resonant frequencies of the system. This feature of the inventionmakes this embodiment even more versatile.

It is contemplated that the annular coil 45 may be the only coilassociated with the device of this invention in at least one embodiment.Thus coil 37 would not be present in the device of FIG. 6, although ring35 or some other support member would be needed to hold bobbin 47 inplace. In this manner, core 29, which is suspended by springs 27 and 49will cause mirror 13 to oscillate as previously described.

In FIG. 7, a complete assembly is shown with both coil 37 and coil 45 inplace. This assembly optimizes the ability to provide movement to amirror or other optical device on an axis. Covers 59 and 61 provideprotection primarily against excessive deformation of springs 27 and 49so that they do not exceed their elastic limit.

The device shown in FIG. 7 is configured to move mirror 13 in the mannershown in FIG. 1, where, for example, a laser 11 produces a twodimensional pattern 15 for use as a scanner. FIG. 8 shows substantiallythe same device except that shaft 17 is eliminated and mirror 67 isplaced directly on the center 38 of core 29. In this configuration, alaser beam or other light can be directed toward the device along theaxis of the device, rather than generally perpendicular to the axis.This modification permits even greater flexibility in design of ascanning device or any of the many uses for the device of thisinvention. In both cases, movement is provided on the axis of thedevice, by current flow in coils which are within the magnetic field ofthe core to cause relative movement between core and coil or coils asthey are suspended by springs and the like.

Turning now to FIG. 9, torsion springs 27 and 49 are flat torsionsprings with two spirals symmetrically arranged, so that the arrangementhas four spring constants. One spring constant is in the z direction,shown along axis 19 while another spring constant is in the rotationaldirection shown by arrow 21. In addition, there are two springconstants, each in one of the x and y directions. X and y directions areperpendicular to each other, but actually represent angulardisplacements about the center of shaft 17, or 31, between the twosprings at point A, which is midway between the two springs of 27 and49. Thus, if a mirror is attached to the end of shaft 17, it may be madeto execute oscillatory rotations in direction R as well as rocking orprecessing motion in the x or y directions. By adjusting parameters ofthe spring such as stiffness, the number of turns of spirals, overalllength of the spirals, and inertia of the mirror shaft system and thelike, it is easy to obtain a desired rotational motion caused by theresonant frequency of the assembly in the rotational direction at aparticular frequency as well as resonant motions in the x and ydimensions. This resonant rotational frequency can be made several timeshigher than the resonant frequency for rocking in either the x or ydirection. Thus, movement of mirror 13 on shaft 17 will produce a rasterlike pattern which will retrace itself as long as the current suppliedthrough the windings 37 continues to be at resonances as describedherein.

Shown in FIG. 10 is another version of the present invention in whichmirror 13 is moved by shaft 17 as a second coil 71 is wound about core35a. Core 35a includes a non-magnetic spacer which separates twoconductive ring halves. When coil 37 is used as a drive coil, secondcoil 71 will function as a sensor coil. Movement of rotor 29 aspreviously described will induce a significant back EMF into the secondcoil 71, and this EMF can be detected. This will allow for feedbackcontrol of this drive coil 37 to modify motion of core 29.

Shown in FIG. 11 is a laser generated pattern which is two dimensional.The pattern is generated by moving mirror 13 in the direction of arc 23and rotation about Z axis 19 as depicted by arrow 21. By combining bothmotions and causing the rotational oscillation to be slower than noddingmotion or linear motion of mirror 13 in the direction of arc 23, araster pattern 202 is generated as shown.

Such a pattern can be generated by the device shown in FIG. 12, which isan exploded view of an additional embodiment. The device shown in FIG.12 includes an annular ring 77 which has a gap 79 and a coil 81 wrappingthe periphery of the ring 77 at a point 180° radially from gap 79. Core29 is suspended between springs 83 and 85 by setting the top 84 andbottom 86 of magnetic core 29 into the center portions of springs 83 and85 respectively. Core 29 oscillates without contact with ring 77 andthus can move shaft 17 and therefore move mirror 13 in response tofrequencies passed through coil 81. When springs 83 and 85 are stiff andan alternating current is introduced into coil 81 at resonant frequencyof the mass and the spring combination for movement in a particulardirection, such as in the direction of arrow 23, a first motion isachieved to cause reflective beam 201 to trace a vertical pattern alongthe Y axis 203. The rotational movement causes the reflective beam toprovide the component on the X axis 204.

Turning now to FIG. 14, a method for generating substantial rotationaltorque in the core 29 is illustrated as follows. Lines of flux, astypified by arrows 113 emanate from the coil 29 and penetrate coil 81which is wound about the core 77. When coil 81 is energized withalternating current I, torque will be introduced into the core 29causing it to oscillate in a rotational direction shown by arrow 21 atthe frequency of the alternating current I being supplied. A magneticfield, depicted by lines of flux 102, will be induced in metal core 77.Gap 79 is included in ring 77 such that flux lines 102 emerge from gap79 as flux lines 103 and 104 to encounter the permanent south pole S ofmagnetic core 29. A stronger torque is thereby induced in core 29compared to that generated by the simple interaction of the field fromcore 29 and coil 81. Thus, as alternating current I is introduced intocoil 81, the strong torque brought about by the use of gap 79 permitsrotation of the core 29 at a frequency well below resonance forrotational motion and at large angles which may be on the order of 30°.Thus, if a high frequency current at the proper resonance frequency isapplied to the coil 81 along with a low frequency alternating current ofsufficient magnitude, the raster scan patter 102 shown in FIG. 11 willbe generated.

Another embodiment similar to that shown in FIG. 12 is shown in FIG. 13.In this design, a single spring 83 is used to flexibly support core 29on shaft 17. The top and bottom portions of shaft 17 are supported inbearings 87 and 89, which are located in plates 88 and 90 respectively.Use of bearings 87 and 89 prevent motion in any of the axes previouslydescribed, thereby allowing only rotational movement about axis 19 inthe direction of dual arrow 21.

Torque forces in the device shown in FIG. 13 are again illustrated inFIG. 14. The gap 79 of ring 77 cooperates with coil 81 to produce atorque about the Z axis 19. As current I in coil 81 is an alternatingcurrent, movement in the direction of arrow 21 is in both clockwise andcounterclockwise directions about axis 19. A different embodiment isshown in FIG. 15 when it is necessary to increase the torque and damperresonant frequencies. Instead of a gap, ring 77 includes a radiallyinwardly facing ferromagnetic screw 91 which is threaded to adjustablyvary the distance between the screw and the core 29. FIG. 15 shows thedevice in an exploded position with the shaft 17 supported by bearings87 and 89, in bearing plates 88 and 90 as previously described. Spring83 allows for reaction to torque which is induced in core 29. In FIG.16, the flux lines 142 encounter the south pole S of core 29 as shown byarrows 149. Since screw 91 is threaded to adjustably vary the gap 150between the screw 91 and the core 29, the induction of a torque on core29 can be varied. Maximization of the torque at a particular frequencyrequires a balancing of the current I in coil 81 and the gap 150 betweencore 29 screw 91. Also, as gap 150 is closed, resonant motion which mayproduce unwanted overshoot of rotational motion upon starting the devicemay be dampened and thereby reduced.

Shown in FIG. 17 is yet an another embodiment of the present inventionwhich provides for increased torque about the Z axis as shown by arrow21. In this embodiment core 29 has flat faces 93 to provide space forcoil 95 and 97 in areas generally shown at 106 and 107. Thus, the southpole S of core 29 can be closer to gap 79 and the North Pole N closer tothe ferromagnetic ring 77 so that an increased torque is again achieved.

Shown in FIG. 18 is yet another embodiment of the present inventionwhich may be driven at a frequency well below resonance and yet is ableto execute large X or Y displacements on the order of 30 degrees. Thiscapability is well suited to generation of raster patterns and thedevice is amenable to extremely compact mounting on the surface of aprinted circuit board.

The device shown in FIG. 18 includes a solenoid coil 301 wrapped about aferromagnetic core 300 shaped like a dumbbell. The core 300 is used toincrease the strength of the magnetic field produced by coil 301.

When coil 301 is energized with alternating current, core element 29will be caused to execute oscillating displacements as indicated bydouble arrow 23. These displacements may be made using large and verylow frequency as compared to the natural resonant frequency for suchmotion due to the intense field produced by coil 301. At the same time,if a resonant frequency for motion in another direction which isrelatively high is superimposed on the low frequency applied to coil 301or it is applied to annular coil 45, a raster pattern or some other twodimensional patten may be generated. Such a pattern is illustrated inFIG. 19.

FIG. 20 illustrates a device which can accept an input light beam 200and cause it to be scanned so that the scanned beam 210 emerges from ittraveling generally in the same direction as the light that entered it.With this device it is possible to linearly arrange a light source 11with the scan device 350 in line with outgoing beam 210 as shown in FIG.21 and thereby greatly simplify the optical layout of a scanner. Inaddition this arrangement can be built into an extremely compact andnarrow enclosure such as a cylindrical tube on the order of only onehalf inch in diameter.

In the operation of the device of FIG. 20 a light beam 200 from lightsource 11 enters aperture 330 and passes through an opening 328 insuspension 320 whereupon the beam is reflected by a first fixed mirror326. After reflection by mirror 326, the beam travels along path 202 andis again reflected by a second moveable mirror 324 and emerges alongpath 210 from the device passing through aperture 335. Note that theinput beam 200 is generally parallel to and moves in the same directionas the output beam 210 except that beam 210 is scanning about thatdirection.

Scanning is achieved when magnetic core 29, attached to flexiblesuspension 320 is set in motion by applying alternating current to coil45 and moveable mirror 325 participates in the motion of core 29 therebycausing outgoing beam 210 to scan.

Moveable mirror is shown mounted on a wedge 322 and stationary mirror326 is fixed to the body 327 of the device at an angle so that thereflective surfaces of both mirrors 324 and 326 face each other and areparallel. This is considered the best embodiment but modifications arepossible. Also the device can be operated in reverse by first reflectingan input beam from the moveable mirror 325 in which case the output beamwould then emerge from aperture 330 after reflection from fixed mirror326.

By driving coil 45 of the device of FIG. 20 with an appropriate mix offrequencies it is possible to generated two dimensional scan patterns asis accomplished in other embodiments of the present invention.

While particular embodiments of the present invention have beenillustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made therein within thescope of the following claims.

What is claimed is:
 1. A device for providing angular displacement of amirror about an axis in a direction selected from at least one of the Xand Y directions or rotational movement of said mirror about the Zdirection with respect to said axis in combination with angulardisplacement of said mirror about said axis in a direction selected fromone of the X and Y directions, comprising:a magnetic core elementproducing a magnetic field, said core element being rigidly coupled tosaid mirror and providing at least two movements selected from the groupconsisting of displacement in the X direction, displacement in the Ydirection, and rotation about the Z axis; coil means proximate said coreelement for introducing a distortion force in said core element in atleast one of said X and Y directions or rotation about the Z directionin combination with angular displacement of said axis in a directionselected from one of the X and Y directions; and mounting means forsuspending said core element with respect to said coil means to permitrelative movement therebetween in response to said distortion force. 2.The device of claim 1, wherein said mounting means comprises a springmounting said core element to said coil means.
 3. The device of claim 1,wherein said coil means includes a coil surrounding said axis and spacedfrom said core element.
 4. The device of claim 1, wherein said mountingmeans includes a flexible membrane.